Back-lit outdoor signs and awnings are known in the art. Typically, such signs and awnings include pressure-sensitive vinyl graphics on a suitable translucent carrier such as rigid acrylic or some other flexible sign-face material. These prior art constructions, however, suffer from several deficiencies including, without limitation, solar degradation of the color graphics and environmental dirt contamination on the face of the graphics.
It is also known in the prior art to address such deficiencies of the prior art used color-pigmented polyvinyl fluoride ("PVF") film, such as DuPont.RTM. TEDLAR.RTM. film. TEDLAR is a thin, generally clear film that is dirt-resistant and exhibits excellent UV resistance. Such color-pigmented film, however, is difficult and expensive to produce, and it is only commercially available in a relatively few standard colors which do not satisfy the sign industry's requirements to provide custom colors.
Another approach to solving the problems of the prior art has been to laminate a pressure-sensitive colored film (sold commercially as SCOTCHCAL.RTM.) to a white fabric base formed by vinyl-coating a nylon mesh (PANAFLEX.RTM.). This process produces a flexible sign material but this material wears poorly, is subject to streaking and is expensive to produce.
Still another proposed solution to the deficiencies of the prior art has been to silkscreen colors onto TEDLAR film using a flatbed screen printing machine. This approach facilitates the formation of custom-colored PVF films but is not commercially practicable because the film can only be printed in a discrete (i.e., not continuous) manner. The size of each portion printed is limited to the area of the flatbed screen, and it is difficult to provide consistent coloration across multiple print cycles. In the flatbed silkscreen process, the heat in the inking room generally causes variation in coloration, e.g., pigment density and translucency, from screen to screen. Manufacturers of such silkscreened PVF film recommend that the silkscreened film be cut and ends be matched for coloration before application to a sign. In addition, it is not possible to perfectly match (register) the ink from screen to screen in such prior art techniques. That is, it is not possible to get an invisible seam at the join between ink laid down from one screen and ink laid down adjacently. There is either an open area, i.e., an uninked area, of film, or an overlapped area at the join. The product resulting from the silkscreen process is unacceptable and extremely expensive to produce. This process cannot be used effectively on a commercial scale.
Heretofore, long lengths of translucent ink-coated film, with essentially uniform ink coloration along the entire length and which are devoid of ink seems, have not been available. The sign and awning industry has been plagued by limitations in manufacturing methods, which have tended to make the production of large signs an expensive proposition. The need for removal of such limitations has been apparent for a very long time.
There is therefore a need to provide an improved method of manufacturing translucent colored pressure-sensitive clear vinyl films for use in the sign and awning industry which overcome these and other problems of the prior art and which improve quality and reduce manufacturing cost.